Fluoxetine Inhibition of CYP3A4 Potentiating Adrenal Suppression and Peptic Ulcer Disease from Intra-Articular Triamcinolone Injections

Abstract

Dear Editor: The cytochrome P450 3A4 (CYP3A4) system metabolizes nearly half of all hepatically cleared drugs, and can result in clinically relevant drug interactions including elevating serum levels of exogenous steroids ⇓. Fluoxetine is an example of a CYP3A4 inhibitor in common use, and has been associated with elevated serum concentrations of antipsychotics and warfarin, but has no prior documentation of effecting metabolism of glucocorticoids ⇓. While metabolism of glucocorticoids and their long-term side effects may be managed in patients with a clear history of glucocorticoid use, persistent elevation of injectable steroids as a result of the CYP3A4 system may be overlooked and result in complications ⇓. We report a case of a 35-year-old White female presenting to the hospital with a 6-month history of burning epigastric abdominal pain unchanged by meals, with one episode of nonbloody emesis prior to presentation. Past medical history included major depressive disorder, gastroesophageal reflux disease, and chronic hip and knee pain. The patient's home medication included fluoxetine 60 mg, lactulose 10 mg/15 mL, zolpidem 5 mg, and potassium …